John Deere 310 Hydraulic Leak

[kidroc2133]

I have a leak at the control valve of my 74' JD 310. There was no o ring on the top of the control under the plastic rubber and washer. I put one there and I still have a leak. Now it looks like the top will unscrew according to the diagram and a o ring goes there. Is it accessible from the top or do you have to go in from the bottom and take all of it out? I attached a diagram of what I am talking about. I replaced number 11 o ring. Need to replace Number 19 o ring.

 

[K5lwq]

I believe you can do it from the top.